With rapid growth of video and cloud services, operators pay special attention to flexibility of optical network construction and reduction of costs n optical network construction, operation, and maintenance. A network node requires cross-connections in more direction dimensions (or, in other words, transmission paths). By using a reconfigurable optical add/drop multiplexer (ROADM), an operator can perform dimension switching remotely and automatically instead of replacing a fiber connection manually by visiting a site in traditional practices, which meets a requirement for dynamic connections on a network. To meet efficiency and flexibility requirements of a high-speed optical communications network, the ROADM serving as a network cross-connection core needs to develop continuously.
At present, the ROADM switches a direction dimension primarily by using an optical cross connect (OXC). One OXC includes multiple input optical modulators and multiple input optical modulators. Each input optical modulator corresponds to one beam of input signal light, and each output optical modulator corresponds to one beam of output signal light. A cross-connect capability (that is, the number of output optical modulators that can be covered by one input optical modulator, or, in other words, the number of input optical modulators capable of covering one output optical modulator) of the optical modulator, which serves as an core component of the OXC, determines a direction dimension to which the OXC can switch, or, in other words, determines the number of input optical modulators and output optical modulators included in the OXC.
Therefore, the ROADM in the prior art may be unable to meet currently growing network requirements and user requirements due to the limited cross-connect capability of the optical modulator.